The investigation is directed towards characterizing the microsomal drug and insecticide metabolizing enzymes in selected insect species and comparing their properties with the hepatic microsomes from mammals. Studies currently in progress are associated with microsomal enzyme induction in the southern armyworm (Prodenia eridania) and the effect of these compounds (alkylbenzenes, 3,4-benzopyrene) on delta-aminolevulinic acid synthetase. Insect epoxide hydrases are also being characterized and the effect of various inhibitors evaluated.